This is something that a lot of people struggle with, according to a Harris Interactive survey commissioned by WhitePages. The survey found that 20 percent of adults in the United States think their address book is messy, incomplete, or out-of-date, and 50 percent say they have duplicate contacts. Hiya allows users to merge duplicate contacts and to ask their friends for more up-to-date information.

There are other contact management solutions out there, acknowledged Hiya senior product manager Amanda Bishop — in fact, things may be getting more competitive as Comcast-owned social networking service Plaxo plans to relaunch its product in a way that refocuses on its original goal, managing users’ address books. But Bishop said that Hiya brings a number of WhitePages’ technology advantages to the problem.

Most importantly, she said Hiya does the best job of actually spotting duplicate contacts. For example, when she tried to merge duplicates in the same list of contacts in both Hiya and Google Contacts, Hiya spotted a number of duplicates that Google didn’t (usually when one of the entries was incomplete or misspelled).

Another cool feature allows you to ask your contacts to provide missing information — for example if you only have someone’s email address and want their phone number as well. This still works if your contact isn’t a Hiya member. They’ll just get an email with a link, then they can submit information on the Hiya website without registering themselves.

Other features include the ability to see which contacts are in or near a new city when you’re traveling, and to fine-tune the synchronization between your different address books. You can fully synchronize your iPhone, Google, and Hiya address books, or only synchronize them one way (so that changes in Hiya aren’t automatically pushed to your other address books), or not synchronize them at all.

Of course, you can also pull contact data from WhitePages, and you’ll receive notifications when WhitePages updates the listing for one of your contacts. (None of your private contact data will get shared with WhitePages, Bishop said.)

The Hiya service started its private beta test last October and is now entering the public beta phase. Outlook, Android, and BlackBerry versions are in the works. There’s no immediate pressure to make money from the app, Bishop said — it’s free for now, and while the company will consider adding premium features that users have to pay for later, it’s also looking at other revenue options.